KERATINOCYTE GROWTH-FACTOR IN INFLAMMATORY BOWEL-DISEASE - INCREASED MESSENGER-RNA TRANSCRIPTS IN ULCERATIVE-COLITIS COMPARED WITH CROHNS-DISEASE IN BIOPSIES AND ISOLATED MUCOSAL MYOFIBROBLASTS

Inflammation in the gastrointestinal tract is associated with increase d epithelial cell proliferation. Keratinocyte growth factor (KGF) is a n epithelial cell mitogen widely expressed by mesenchymal cells subjac ent to the epithelial cells. In this study, we have investigated the e xpression and distribution of KGF in normal and diseased (Crohn's dise ase and ulcerative colitis(UC)) intestine by quantitative competitive reverse-transcriptase polymerase chain reaction in whole biopsies and purified lamina propria myofibroblasts and by in situ hybridization. A nalysis of whole mucosal biopsies reveals significantly higher numbers of KGF mRNA transcripts in UC compared with Crohn's colitis and contr ol colon (P < 0.001), KGF transcripts were also elevated in Crohn's il eitis compared with normal ileum. ht situ hybridization showed a marke d increase in cells expressing KGF mRNA throughout the lamina propria in both UC and Crohn's tissue. In Crohn's disease, positively hybridiz ing cells were only rarely seen in the submucosa but mere abundant aro und the bases of the crypts and were not associated with lymphoid aggr egates, In purified mucosal myofibroblasts, increased (15- to 20-fold) KGF mRNA expression was seen in UC compared with control and Crohn's tissue. These results confirm and extend earlier studies showing that KGF transcripts are elevated in inflammatory bowel disease, but they s how for the first time that transcripts are higher in UC than Crohn's disease because of increased production by mucosal mesenchymal cells.